1. Field of the Invention
The present invention relates to apparatus and methods for reducing blue light hazards, and more particularly, relates to apparatus and methods that reduce blue light hazards utilizing visual persistence effect, polarization of light and phase of light.
2. The Prior Arts
As technology advances, 3C products such as smart mobile devices and tablet computers nearly become necessities for each citizen. Not only are these 3C products used during commute, in the meetings and during break times, but they are also often used in bed right before a user goes to sleep in a dimly lit environment. Thus, each citizen may end up spending hours on these devices every day.
The visible light emitted by smart mobile devices or tablet computers are considered as strong light, and such visible light may include various colors such as the white, red, orange, yellow, green, blue, indigo and purple visible light. FIG. 1a is a schematic diagram illustrating the spectrum of white light. As shown in FIG. 1a, the spectrum of white light can be categorized into a waveform a and a waveform b. The blue light wavelength in the waveform a is at 450 nm, and the blue light wavelength in the waveform b is at 462 nm. From the graph, it can be seen that the intensity of blue light in the white light are at their peaks in both waveform a and waveform b. Therefore, it is clear that the blue light has the strongest effect on human eyes amongst all colors of visible light.
FIG. 1b is a schematic diagram illustrating the relationship between time and the intensity of blue light of 3C products. As shown in FIG. 1b, once conventional 3C products are turned on, these products will continue to emit blue light until they are turned off again. Images and color are formed when the visible light emitted by 3C products enters the macula area of a human eye ball, thereby generating visions. However, blue light, indigo light and purple light are the types of visible light with stronger energy. These lights will pass through cornea and crystal body to enter macula area directly, thereby damaging the photoreceptor cells in the macula area. Age-related macular degeneration is a medical condition developed as a patient ages. When a user looks into a 3C product screen for a long period of time, the chronicle irritation caused by such action could lead to inflammation and swelling of the macula area, and could further lead to the formation of drusen in the center of the macula area. If any of the drusen ruptures and starts to bleed, it could compromise the vision at the central part of a patient's view range. This condition may prevent the patient from looking directly to the front to see and end up squinting; in the end, this condition could result in the patient losing his vision.
Another reason for the blue light being hazardous to the eye is its short wavelength. Blue light is easily scattered because of such short wavelength; as a result, it requires a greater effort for human eyes to focus. Consequently, ciliary muscle is tensed up and unable to relax, and the user may easily experience fatigue and soreness in the eyes when looking into the blue light. Pseudomyopia is another possible hazardous outcome of such situation. If ciliary muscle is unable to relax properly for a long period of time, pseudomyopia may actually develop into myopia, and the degree of myopia may start to increase.
Due to the above drawbacks of 3C products regarding blue light hazard, there is a need for the industry to develop an apparatus and method that is capable of effectively reducing such blue light hazard.